Engine fuel pump



Mayflfs, 1945. W., V, FALCON 2,375,906

ENGINE FUEL PUMP Filed May 14, 1942 jv /ao '98 -I 174A 252' l /eb 2.36 /94 I9@ zalf Fi g 2 ue/nor:

J M, @NMAC/gm ornejs.

atented May l5, i945 STATES PATENT OFFICE 2 Claims.

This invention relates generally to compression ignition engines and more particularly to fuel pumps therefor.

It is the primary aim and object of the present invention to provide a simple and sturdy controller for a fuel pump which may be readily manipulated at any time to vary the fuel quantity delivered by said pump for the purposes of starting, stopping, and changing the speed of, a compression ignition engine.

It is another object of the present invention to provide a controller which starts ejection of fuel `from the pump progressively earlier in a piston cycle the larger the quantity of each fuel charge becomes, so that the fuel ejection terminates for all inten-ts and purposes at substantially the same period in each piston cycle regardless of the speed of the engine.

The foregoing and other objects of the invention, together with means whereby the latter may be carried into effect will best be understood from the following description of an illustrative embodiment shown in the accompanying drawing, in which:

Fig. l is a fragmentary section through an engine having a fuel pump and a controller therefor which embodies the present invention.

Fig. 2 is a section through the fuel pump and controller shown in Fig. l, showing certain elements thereof in a different relative position.

Fig. 3 is an enlarged fragmentary section througth the fuel pump and controller shown in Figs 1 and 2.

Referring to Fig. 1, there is disclosed a fuel pump which is mounted on top of an engine structure. The pump casing |14 fits into a bore |16 in the cylinder head |12 and is effectively sealed from the outside by a gasket |18. Re

ciprocable in a bore |80 in the pump casing is a sleeve plunger |82 in which the stem |84 of another plunger |86 in said bore is reciprocable. Also fitted into the bore |16 in the cylinder head and inter-engaged as at |88 with the lower end of the pump casing |14 is a nozzle |90 which has an annular recess |92 adjacent to, and of a slightly larger diameter than, the bore |80 in the pump casing, a frusto-conical recess |80 which is a continuation of the annular recess |92, and a discharge passage |96. Provided in the cylinder head |12 and the pump casing |14 is an inlet duct |98 which provides communication between the bore |80 in the pump casing and a conduit 200 which in turn is in communication with a supply of fuel that is preferably under a low pressure. The sleeve plunger |82 is normally urged in the direction of the arrow 20,2 by means of a compression spring 204 interposed between the pump casing |14 and a flange 206 on said sleeve piston, and the other plunger |86 is normally urged in the same direction by means of a compression spring 208 which is interposed between the flange 206 on the sleeve plunger and a conventional spring retainer 2|0 at the adjacent end of the valve stem |84. The spring 208 cooperates with a rocker 2|2 to reciprocate the sleeve plunger |82. The rocker 2|2 is journalled at 2M on a bracket 2|6 and' has a forked end 2I8 which straddles the spring 208 and engages the ange 206 on the sleeve plunger. The other end of the rocker 2|2 is provided with a set screw 220 whose ball-shaped end 222 cooperates with a push rod 224 which is reciprocated through an invariable stroke from the crank shaft in any suitable manner. The sleeve plunger |82 will assume the position illustrated in Fig. 2 at the upper limit of its stroke, and will assume the position shown in Figs. 1 and 3, substantially ush with the adjacent end of the bore in the pump casing, at the lower limit of its stroke. Above the stem |84 of the plunger |86 is a stop 2-30 against whichsaid stem strikes when the sleeve plunger |82 moves into the upper end position of its stroke as shown in Fig. 2, thereby admitting the plunger |86 sufficiently into the bore |80 of the pump casing to intercept communication between said `bore and the annular recess |82 in the nozzle |80. By virtue of the explained movements of the plungers |82 and |86, they also denne in the bore |80 of the pump casing a ring shaped space 232 which is, moreover, in communication with the inlet duct |98 so that fuel is admitted into said space. The spring 208 is weaker than the spring 204 so that the sleeve plunger |82 will follow the rocker 2|2 upwardly throughout its operating range even though the stem |84 of the plunger |86 engages the stop 230 considerably before the sleeve plunger reaches the upper limit of its stroke On the following downward stroke the sleeve plungerseated on the frusto-conical recess |94 in the nozzle |80. The crown 234 of the plunger |36 is provided with a plurality of shallow grooves 230 through which the fuel charge must pass to the discharge passage |96. Hence, after the crown 234 of the plunger |86 has become seated on the frusta-conical recess |94 in the nozzle, and on continued descent of the sleeve plunger |32, the fuel charge is forced through the ine clearances between the plunger |36 and the annular recess |92 in the nozzle and then through the shallow grooves 236 in the crown 234 from which the fuel escapes at high velocity and finely atomized into the combustion chamber 240.

The stop 230 is preferably in form of an eccentric on a manually rotatable shaft 242, thus providing for axial adjustment of the plunger |86 (Fig. 2). Axial adjustment of the plunger |88 as explained results in a variation inthe quantity of the fuel charge, as will be readily understood. Thus, little fuel may be admitted to the combustion chamber 240 for starting purposes, and more fuel may be admitted therein commensurate with speed and load conditions of the engine, by merely manipulating the eccentric shaft 242. On turning said shaft 242 so that the eccentric portion 244 is in operative alignment with the stem |84 of the plunger |86, the latter will remain in engagement with the sleeve plunger |82 throughout the reciprocation of the latter and no fuel will be delivered by the pump, causing the engine to stop.

I claim:

1. A fuel pump comprising a casing having a bore, an inlet duct leading into said bore, and a discharge nozzle provided by a diametrlcally enlarged end of said bore terminating in an apertured seat, a sleeve plunger slidably fitted in said bore, another plunger also slidably iltted in said bore and having a stern extending with a sliding t through and beyond said sleeve plunger and a seating surface with a shallow depression forming the sole passage between said enlarged bore end and the aperture in said seat when said seating surface engages said seat, spring means normally retracting said sleeve plunger beyond said inlet duct, a stop engagedby the stem of said otherplunger when the latter is between said discharge nozzle and inlet duct, spring means urging the stem of said other plunger into engagelnent with said stop, and means for reclproi eating said sleeve plunger past said inlet duct, the enlarged bore end of said discharge nozzle and slidably fitted portion of the other plunger being so coordinated that the latter is wholly within said enlarged bore end when said seating surface engages said seat.

2. A fuel pump as set forth in claim 1, in which said stop is an angularly adjustable cam to vary the position of said other plunger when the stem of the latter engages said cam.

WILLIAM V. FALCON, 

